1. Field of the Invention
The present invention relates to an image forming apparatus, a method for controlling the image forming apparatus, and a recording medium.
2. Description of the Related Art
In the market, image forming apparatuses capable of forming an image using a sheet of a size other than a regular-size sheet of the A series or the B series according to the Japanese Industrial Standards (JIS), or the inch series in European and American standards have been put to practical use.
As settings and systems for using such sheets of irregular sizes (free size or user-set size), the following systems have been proposed. The sheet sizes of irregular sizes are much in demand not only in general users of consumers but in the printing industry.
Examples of known setting methods and detection methods of an irregular sheet size include the following methods. A first method is a setting method called a free size. The sheet size includes a length (hereinafter, referred to as X size) in a sheet conveyance direction and a length (hereinafter, referred to as Y size) in a sheet width direction.
In the free size, in response to user's setting operation of a sheet on a manual feed tray of an image forming apparatus, a screen for setting a sheet size is displayed on an operation panel. Then, if the user selects the free size, the sheet size of the free size can be set (see 701 in FIG. 6).
When such setting is performed, the X size and the Y size are indefinite. Then, at the image forming apparatus side, processing for automatically detecting the size is performed. In such a case, the image forming apparatus detects the set X size by conveying the sheet and by using a sensor for detecting the leading edge or the trailing edge of the sheet in the conveyance path.
On the other hand, the Y size is detected using a guide that is fit when the sheet is set on the manual tray. In the method, the user's setting operation is not so complicated. However, there is a problem that the accurate size of the X size is not determined until the sheet is conveyed.
Meanwhile, in a configuration where formation of an image on a transfer member is started before conveyance of a sheet is started in an image forming apparatus, the image formation has to be performed before the sheet size is determined.
In such a case, by the above-mentioned method, at the time the sheet size is determined, the image formation of the size larger than the sheet size has already been performed. Accordingly, it is necessary to collect and clean the toner of the image that has not been transferred from the transfer member to the sheet. Otherwise, inside of the image forming apparatus may become dirty.
A second method is a setting method called a user-set size. In the method, similarly to the free size, in response to user's setting operation of a sheet on a manual feed tray of an image forming apparatus, a screen for setting a sheet size is displayed on an operation panel. Then, the user sets a user-set size on the panel.
In the setting, by inputting the X size and the Y size in millimeters or inches by the user, the problem in the free size that the sheet size is not determined before the image formation start can be avoided. Accordingly, the method can also be applied to a configuration in which the image formation is started before the conveyance of the sheet is started in the image forming apparatus.
However, in this setting, the user is required to correctly set the X size and the Y size to the image forming apparatus, and this may complicate the setting operation of the user. Further, the user may mistakenly reversely set the vertical direction and the width direction of the actual sheet size.
In Japanese Patent Application Laid-Open No. 2004-004622, in a monochromatic mode, an apparatus is operated in the free size, and in a color mode, the apparatus is operated in the user-set size that requires input of an X size and a Y size. By this technique, the known art for reducing the complication in the user's setting operation has been proposed.
Meanwhile, Japanese Patent Application Laid-Open No. 2005-283874 has proposed a known art for reducing the complication in the user's setting operation by detecting the size of a sheet of an irregular size by reading with a document positioning plate of a document reading device included in an image forming apparatus and reflecting the detected size to a manual feed sheet size.
However, in Japanese Patent Application Laid-Open No. 2004-004622, apart of the settings is omitted depending on the color mode, and accordingly, the problem in the complication in the user's setting operation is not solved. In the case of Japanese Patent Application Laid-Open No. 2005-283874, it is assumed that the original size is the same as the manual size. Accordingly, the user is required to once set the sheet on the document positioning plate, perform the reading operation, and set the sheet to the manual feed tray again.
Further, to a configuration of a printer model that does not have the document reading unit, Japanese Patent Application Laid-Open No. 2005-283874 cannot be effectively applied. Thus, according to the techniques of Japanese Patent Application Laid-Open No. 2004-004622 and Japanese Patent Application Laid-Open No. 2005-283874, in an image forming apparatus that can perform feeding of a sheet material and image formation to the sheet material in parallel, a sheet of an irregular size cannot be determined without user's burden in the operation.